| Project/Area Number |
14340102
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
固体物性Ⅱ(磁性・金属・低温)
|
|---|
| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
|---|
Principal Investigator |
OKUDA Yuichi Tokyo Institute of Technology, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (50135670)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NOMURA Ryuji Tokyo Institute of Technology, Graduate School of Science and Engineering, Research Associate, 大学院・理工学研究科, 助手 (00323783)
|
|---|
| Project Period (FY) |
2002 – 2004
|
| Project Status |
Completed (Fiscal Year 2004)
|
| Budget Amount *help |
¥14,200,000 (Direct Cost: ¥14,200,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2002: ¥6,900,000 (Direct Cost: ¥6,900,000)
|
|---|
| Keywords | Superfluid 3He-B / P-wave super fluid / surface bound state / surface elastic wave / transverse acoustic impedance / pair breaking / order parameter collective mode / 粘弾性体 / 超流動3He-B / P-波超流動 / 表面束縛状態 / 表面弾性波 / 横波音響インピーダンス / 対破壊 / オーダーパラメーター集団励起 / フェルミ液体 |
|---|
| Research Abstract |
3He sets into the P-wave spin-triplet super fluid phase at around 1 mK. Order parameter of the super fluid has a lot of internal degrees of freedom and hence it can have many superfluid phases. Unfortunately, however, there are only two phases realized ; BW-state(B-phase) and ABM-state(A-phase). Superfluid 3He-B is very sensitive against the solid wall. The perpendicular component of the wave function of with respect to the wall, which is denoted as Δ_〓(k), has a property of odd function near the wall. That is, Δ_〓(-k)=-Δ_〓(k). Due to this property, Δ_〓(k) gradually recovers to the bulk value as the distance from the wall increases with the characteristic length of several times of the coherence length ξ, whereasΔ_// exhibits no effect of the wall. ξ is typically several nanometers. As a result of this spatial variation of Δ_〓(k), there comes out the surface state inside the gap at the wall position. This surface state is called as "Andreev surface bound state", which is a typical feature of P-wave superfluid at the boundary. The property of the surface bound state crucially depends on the boundary condition at the wall. If the reflection of quasi-particles at the wall is diffusive(which is often the case with the ordinary wall), the bound state is not δ-function like, but has wider energy width. These surface properties of superfluid 3He-B is, of course, predicted by the theory, has not been studied experimentally yet. The reason is that we had no relevant probing techniques. In the present project, we succeeded in detecting this surface bound state, by the precise measurement of the acoustic shear motion of AC-cut quarts transducer with proper resonance frequencies. The signature of the surface bound state was detected as a kink of in the real part of the impedance and in the cusp of the imaginary part of it. The experimental result is well reproduced by the numerical calculation of the shear impedance by the Green function model.
|
